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Secondary Organic Aerosol Formation From Select Volatile Organic Compounds
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Book Synopsis Secondary Organic Aerosol Formation from Select Volatile Organic Compounds by : Chia-Li Chen
Download or read book Secondary Organic Aerosol Formation from Select Volatile Organic Compounds written by Chia-Li Chen and published by . This book was released on 2015 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis enhances our understanding of secondary organic aerosol (SOA) formation from select anthropogenic sources including polycyclic aromatic hydrocarbons (PAHs), PAHs mixed with m -xylene and an atmospheric surrogate, and unburned whole gasoline vapors. Major SOA chemical characteristics and physical properties were explored along with SOA formation within the UCR CE-CERT environmental chamber.
Book Synopsis Chemical and Physical Characterization of Secondary Organic Aerosol Formation from Select Agricultural Emissions by : Quentin Gerald James Malloy
Download or read book Chemical and Physical Characterization of Secondary Organic Aerosol Formation from Select Agricultural Emissions written by Quentin Gerald James Malloy and published by . This book was released on 2009 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Speciation Studies for Biogenic Volatile Organic Compounds and Secondary Organic Aerosol Generated by Ozonolysis of Volatile Organic Compound Mixtures by : Hardik Surendra Amin
Download or read book Speciation Studies for Biogenic Volatile Organic Compounds and Secondary Organic Aerosol Generated by Ozonolysis of Volatile Organic Compound Mixtures written by Hardik Surendra Amin and published by . This book was released on 2012 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosols are either emitted directly into the atmosphere or are generated in the atmosphere; the latter process forms secondary organic aerosol (SOA). One of the important sources for SOA is the oxidation of volatile organic compounds (VOCs) by OH radicals, NOx, and O 3. Aerosol can be visualized as suspended solid or liquid particle which is in equilibrium with surrounding gases. The products of SOA formation is a mixture of semi volatile organic compounds and a fraction of the products are condensable under atmospheric conditions. The condensable portion of aerosol is called particulate matter (PM) and these suspended particles can range in diameter from a few nanometers to microns. PM can impact climate through direct and indirect radiative forcing and can degrade air quality by reducing visibility and causing detrimental health effects. SOA can also form indoors, which also contributes to the health risk of PM. The severe impact of PM on human health and climate drives the scientific community to investigate the volatile organic compounds (VOCs) and their potential to form SOA, as well as the factors that alter the efficiency of SOA generation and the type of products. In a similar pursuit, the focus of this dissertation is the investigation of the SOA precursors that are emitted from trees and how they vary as a function of insect infestation. Also, the role of mixtures of VOCs as SOA precursors are investigated; commercial and lab made VOC mixtures are studied for SOA generation, product analysis, and absorption characteristics of aged SOA.
Book Synopsis Insights Into Predicting Secondary Organic Aerosol Formation from Anthropogenic Volatile Organic Compounds by : Lijie Li
Download or read book Insights Into Predicting Secondary Organic Aerosol Formation from Anthropogenic Volatile Organic Compounds written by Lijie Li and published by . This book was released on 2016 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding secondary organic aerosol (SOA) formation is of critical importance to public health and global climate. SOA formation from anthropogenic volatile organic compounds (VOCs) is influenced by NO, precursor molecular structure, oxidation conditions and other factors. This dissertation explores the impact of NO effect and molecular structure for two categories of VOCs at urban atmosphere relevant conditions by utilizing the state of art 90 m3 UCR/CE-CERT chamber facilities.
Book Synopsis Chemistry of Secondary Organic Aerosol by : Lindsay Diana Yee
Download or read book Chemistry of Secondary Organic Aerosol written by Lindsay Diana Yee and published by . This book was released on 2013 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: The photooxidation of volatile organic compounds (VOCs) in the atmosphere can lead to the formation of secondary organic aerosol (SOA), a major component of fine particulate matter. Improvements to air quality require insight into the many reactive intermediates that lead to SOA formation, of which only a small fraction have been measured at the molecular level. This thesis describes the chemistry of secondary organic aerosol (SOA) formation from several atmospherically relevant hydrocarbon precursors. Photooxidation experiments of methoxyphenol and phenolic compounds and C12 alkanes were conducted in the Caltech Environmental Chamber. These experiments include the first photooxidation studies of these precursors run under sufficiently low NOx levels, such that RO2 + HO2 chemistry dominates, an important chemical regime in the atmosphere. Using online Chemical Ionization Mass Spectrometery (CIMS), key gas-phase intermediates that lead to SOA formation in these systems were identified. With complementary particle-phase analyses, chemical mechanisms elucidating the SOA formation from these compounds are proposed. Three methoxyphenol species (phenol, guaiacol, and syringol) were studied to model potential photooxidation schemes of biomass burning intermediates. SOA yields (ratio of mass of SOA formed to mass of primary organic reacted) exceeding 25% are observed. Aerosol growth is rapid and linear with the organic conversion, consistent with the formation of essentially non-volatile products. Gas and aerosol-phase oxidation products from the guaiacol system show that the chemical mechanism consists of highly oxidized aromatic species in the particle phase. Syringol SOA yields are lower than that of phenol and guaiacol, likely due to unique chemistry dependent on methoxy group position. The photooxidation of several C12 alkanes of varying structure n-dodecane, 2-methylundecane, cyclododecane, and hexylcyclohexane) were run under extended OH exposure to investigate the effect of molecular structure on SOA yields and photochemical aging. Peroxyhemiacetal formation from the reactions of several multifunctional hydroperoxides and aldehyde intermediates was found to be central to organic growth in all systems, and SOA yields increased with cyclic character of the starting hydrocarbon. All of these studies provide direction for future experiments and modeling in order to lessen outstanding discrepancies between predicted and measured SOA.
Book Synopsis Characterizing the Formation of Secondary Organic Aerosols by :
Download or read book Characterizing the Formation of Secondary Organic Aerosols written by and published by . This book was released on 2004 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic aerosol is an important fraction of the fine particulate matter present in the atmosphere. This organic aerosol comes from a variety of sources; primary organic aerosol emitted directly from combustion process, and secondary aerosol formed in the atmosphere from condensable vapors. This secondary organic aerosol (SOA) can result from both anthropogenic and biogenic sources. In rural areas of the United States, organic aerosols can be a significant part of the aerosol load in the atmosphere. However, the extent to which gas-phase biogenic emissions contribute to this organic load is poorly understood. Such an understanding is crucial to properly apportion the effect of anthropogenic emissions in these rural areas that are sometimes dominated by biogenic sources. To help gain insight on the effect of biogenic emissions on particle concentrations in rural areas, we have been conducting a field measurement program at the University of California Blodgett Forest Research Facility. The field location includes has been used to acquire an extensive suite of measurements resulting in a rich data set, containing a combination of aerosol, organic, and nitrogenous species concentration and meteorological data with a long time record. The field location was established in 1997 by Allen Goldstein, a professor in the Department of Environmental Science, Policy and Management at the University of California at Berkeley to study interactions between the biosphere and the atmosphere. The Goldstein group focuses on measurements of concentrations and whole ecosystem biosphere-atmosphere fluxes for volatile organic compounds (VOC's), oxygenated volatile organic compounds (OVOC's), ozone, carbon dioxide, water vapor, and energy. Another important collaborator at the Blodgett field location is Ronald Cohen, a professor in the Chemistry Department at the University of California at Berkeley. At the Blodgett field location, his group his group performs measurements of the concentrations of important gas phase nitrogen compounds. Experiments have been ongoing at the Blodgett field site since the fall of 2000, and have included portions of the summer and fall of 2001, 2002, and 2003. Analysis of both the gas and particle phase data from the year 2000 show that the particle loading at the site correlates with both biogenic precursors emitted in the forest and anthropogenic precursors advected to the site from Sacramento and the Central Valley of California. Thus the particles at the site are affected by biogenic processing of anthropogenic emissions. Size distribution measurements show that the aerosol at the site has a geometric median diameter of approximately 100 nm. On many days, in the early afternoon, growth of nuclei mode particles (
Book Synopsis Chemistry of Secondary Organic Aerosol Formation from Reactions of Alkenes with Ozone and Nitrate Radicals by : Huiming Gong
Download or read book Chemistry of Secondary Organic Aerosol Formation from Reactions of Alkenes with Ozone and Nitrate Radicals written by Huiming Gong and published by . This book was released on 2003 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Collection, Speciation and Aerosol Modelling for Volatile Organic Compounds by : Kevin Alan Scott Goodman-Rendall
Download or read book Collection, Speciation and Aerosol Modelling for Volatile Organic Compounds written by Kevin Alan Scott Goodman-Rendall and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Biogenic Volatile Organic Compounds in Atmosphere by : Andebo Abesha Waza
Download or read book Biogenic Volatile Organic Compounds in Atmosphere written by Andebo Abesha Waza and published by LAP Lambert Academic Publishing. This book was released on 2014-12-05 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is one of the biggest challenges facing the world in the 21st century. Human activities, like combustion of fossil fuel result in emissions of different radiation-modifying substances like aerosol particles and greenhouse gases that have a profound influence on our climate system through either by warming or cooling earth's surface. Green leaf volatiles (GLVs) are an important component of biogenic volatile organic compounds (BVOCs) released by vegetation during mechanical damage, herbivory attack, pathogen infection and abiotic stress. They play a major role in contributing to the formation of secondary organic aerosol particles in atmosphere. The main objective of this book was to examine the formation of secondary organic aerosol particles from ozonolysis of various GLVs (trans-2-hexenal, cis-3-hexenol and 3-hexynyl acetate) by using series of chamber experiments performed in humid conditions ( 50% RH).
Book Synopsis Secondary Organic Aerosol Formation from Reactions of Linear, Branched and Cyclic Alkanes with OH Radicals in the Presence of NO[subscript X] by : Yong Bin Lim
Download or read book Secondary Organic Aerosol Formation from Reactions of Linear, Branched and Cyclic Alkanes with OH Radicals in the Presence of NO[subscript X] written by Yong Bin Lim and published by . This book was released on 2008 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Molecular Composition, Volatility, and Formation Mechanisms of Biogenic Secondary Organic Aerosol by : Emma Louise D'Ambro
Download or read book Molecular Composition, Volatility, and Formation Mechanisms of Biogenic Secondary Organic Aerosol written by Emma Louise D'Ambro and published by . This book was released on 2018 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Volatile Organic Compounds by : Tzung-May Fu
Download or read book Volatile Organic Compounds written by Tzung-May Fu and published by . This book was released on 2007 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis quantitatively improves the current understanding of nonmethane volatile organic compound (NMVOC) emissions, as well as the global effect of these emissions on secondary organic aerosol (SOA) production via glyoxal and methylglyoxal formation.
Book Synopsis Small Molecules as Tracers in Atmospheric Secondary Organic Aerosol by :
Download or read book Small Molecules as Tracers in Atmospheric Secondary Organic Aerosol written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Secondary organic aerosol (SOA), formed from in-air oxidation of volatile organic compounds, greatly affects human health and climate. Although substantial research has been devoted to SOA formation and evolution, the modeled and lab-generated SOA are still low in mass and degree of oxidation compared to ambient measurements. In order to compensate for these discrepancies, the aqueous processing pathway has been brought to attention. The atmospheric waters serve as aqueous reaction media for dissolved organics to undergo further oxidation, oligomerization, or other functionalization reactions, which decreases the vapor pressure while increasing the oxidation state of carbon atoms. Field evidence for aqueous processing requires the identification of tracer products such as organosulfates. We synthesized the standards for two organosulfates, glycolic acid sulfate and lactic acid sulfate, in order to measure their aerosol-state concentration from five distinct locations via filter samples. The water-extracted filter samples were analyzed by LC-MS. Lactic acid sulfate and glycolic acid sulfate were detected in urban locations in the United States, Mexico City, and Pakistan with varied concentrations, indicating their potential as tracers. We studied the aqueous processing reaction between glyoxal and nitrogen-containing species such as ammonium and amines exclusively by NMR spectrometry. The reaction products formic acid and several imidazoles along with the quantified kinetics were reported. The brown carbon generated from these reactions were quantified optically by UV-Vis spectroscopy. The organic-phase reaction between oxygen molecule and alkenes photosensitized by [alpha]-dicarbonyls were studied in the same manner. We observed the fast kinetics transferring alkenes to epoxides under simulated sunlight. Statistical estimations indicate a very effective conversion of aerosol-phase alkenes to epoxides, potentially forming organosulfates in a deliquescence event and increasing aerosol mass. Finally, we built a containerless apparatus to study aqueous processing reactions using an acoustic levitator paired with a mass spectrometer. The levitator is capable of trapping droplets with the size of 80-500 [mu]m in diameter for over eight hours. The apparatus is also capable of drying and wetting the droplet in a controllable manner. We performed am example reaction between glyoxal and ammonium sulfate using this instrument, and showed that it could qualitatively monitor aqueous processing reactions.
Book Synopsis Study of Volatile Organic Compounds (VOC) in the Cloudy Atmosphere by : Miao Wang
Download or read book Study of Volatile Organic Compounds (VOC) in the Cloudy Atmosphere written by Miao Wang and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volatile Organic Compounds (VOC), including saturated, unsaturated, and other substituted hydrocarbons, play a major role in atmospheric chemistry. They are primarily emitted by anthropogenic and biogenic sources into the atmosphere; they are also transformed in situ by chemical reactions, and more specifically, by photo-oxidation leading to the formation of ozone (O3) and Secondary Organic Aerosol (SOA). By altering the organic fraction of aerosol particles, VOC modify the Earth's radiative balance through a direct effect (absorption and scattering of solar radiation) or through indirect effect by altering cloud microphysical properties. They also present a direct effect on human health and on the environment.During their atmospheric transport, VOC and their oxidation products, Oxygenated Volatile Organic Compounds (OVOC), may partition between the gaseous and aqueous phases depending on their solubility. Clouds have a significant effect on tropospheric chemistry by redistributing trace constituents between phases and by providing liquid water in which aqueous phase chemistry can take place. Indeed, during the cloud lifetime, chemical compounds and particularly VOC are efficiently transformed since clouds favor the development of complex “multiphase chemistry”. The latter presents several particularities. First, photochemical processes inside the droplets are important in the transformation of chemical compounds. Second, aqueous chemical reactions are efficient and can be faster than the equivalent reactions in the gas phase. This can be related to the presence of strong oxidants such as hydrogen peroxide H2O2 or Transition Metal Ions (TMI), which participate in the formation of radicals such as hydroxyl radicals (HO•) that favor oxidation processes. Furthermore, the presence of viable microorganisms has been highlighted and shown to participate in transformations of the chemical species. Finally, these transformations in clouds are also strongly perturbed by microphysical processes that control formation, lifetime and dissipation of clouds. These processes will redistribute the chemical species between the different reservoirs (cloud water, rain, particle phase, gaseous phase, and solid ice phase). In this frame, the transformation of VOC in the cloud medium can lead to the production of secondary compounds contributing to SOA formation, reported as “cloud aqSOA”. This secondary organic aerosol mass produced during the cloud lifetime could explain in part the ubiquity of small dicarboxylic and keto acids and high molecular-weight compounds measured in aerosol particles, fog water, cloud water, or rainwater at many locations, as they have neither substantial direct emission sources nor any identified important source in the gas phase. This aqSOA mass stays in the particle phase after cloud evaporation implying a modification of the (micro)physical and chemical properties of aerosol particles (particle size, chemical composition, morphology). This leads to modifications of their impacts on consecutive cloud or fog cycles (aerosol indirect effects) and of their interactions with incoming radiation by scattering/absorbing (aerosol direct effect). (...).
Book Synopsis Impacts of Controlling Reactivity and Temperature on Advanced Study of Secondary Organic Aerosol Formation by : Mary Elizabeth Kacarab
Download or read book Impacts of Controlling Reactivity and Temperature on Advanced Study of Secondary Organic Aerosol Formation written by Mary Elizabeth Kacarab and published by . This book was released on 2016 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Secondary organic aerosol (SOA) is formed via the oxidation of volatile organic compounds emitted to the atmosphere from both biogenic and anthropogenic sources. Due to the complexity of atmospheric composition and range of ambient conditions, aerosol models, which are mostly based off observed yields from controlled laboratory chamber experiments, greatly underestimate global SOA formation. To increase the understanding of the formation and properties of ambient SOA, it is imperative to explore ways to improve the complexity of chamber studies while still maintaining a level of control not found outside of the laboratory.
Book Synopsis Characterization of Secondary Organic Aerosol Precursors Using Two-Dimensional Gas Chromatography with Time of Flight Mass Spectrometry (GC×GC/TOFMS) by :
Download or read book Characterization of Secondary Organic Aerosol Precursors Using Two-Dimensional Gas Chromatography with Time of Flight Mass Spectrometry (GC×GC/TOFMS) written by and published by . This book was released on 2013 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oxidation of volatile organic compounds (VOCs) plays a role in both regional and global air quality through the formation of secondary organic aerosols (SOA). More than 1000TgC/yr of non-methane VOCs are emitted from biogenic sources (significantly greater than from anthropogenic sources). Despite this magnitude and potential importance for air quality, the body of knowledge around the identities, quantities and oxidation processes of these compounds is still incomplete (e.g., Goldstein & Galbally, 2007; Robinson et al., 2009). Two-dimensional gas chromatography paired with time-of-flight mass spectrometry (GC×GC/TOFMS) is a powerful analytical technique which is explored here for its role in better characterizing biogenic VOCs (BVOCs) and thus SOA precursors.
Book Synopsis Aqueous Reaction Kinetics and Secondary Organic Aerosol Formation from Atmospheric Phenol Oxidation by : Jeremy Daniel Smith
Download or read book Aqueous Reaction Kinetics and Secondary Organic Aerosol Formation from Atmospheric Phenol Oxidation written by Jeremy Daniel Smith and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic aerosols (OA) are a dominant fraction of particulate mass in the atmosphere, and much is secondary in nature. Secondary organic aerosol (SOA) is formed in the atmosphere from volatile organic compound precursors. Traditional SOA formation pathways involve primarily gas-phase processes: Oxidation reactions of organic gases result in low-volatility products that condense to the particulate phase, increasing aerosol mass. However, in recent years heterogeneous processes, including aqueous reactions, have gained more attention as gas-phase processes often fail to accurately predict observed mass loadings of aerosol in the atmosphere. Aqueous SOA formation is the result of a volatile organic species partitioning to the aqueous phase (clouds, fogs, aqueous aerosols), where they are chemically converted into a non-volatile species that remains in the particulate phase upon water evaporation. In this work we explore the aqueous chemical reaction kinetics and the SOA formation potential of phenols, which are released in large quantities from biomass combustion. Phenols are a broad class of organic compounds with intermediate volatilities (102 - 106 [mu]g m−3 at 20°C) and moderate to high Henry's Law Constants (103 - 109M atm−1), indicating significant partitioning to atmospheric aqueous phases. We begin in chapters 2 and 3 by investigating the aqueous oxidation of the compounds phenol (compound with formula C6H5OH), guaiacol (2-methoxyphenol), syringol (2,6-dimethoxyphenol), and three dihydroxybenzenes (catechol, resorcinol, hydroquinone). For each phenol we examined reactions with two oxidants: hydroxyl radical (*OH) and the triplet excited state of 3,4-dimethoxybenzaldehyde, which is also emitted from biomass combustion. Triplet excited states (3C*) have been widely studied in surface waters (oceans and lakes) but are a novel oxidation pathway in atmospheric aqueous phases. The precursors for triplet excited states are essentially brown carbon: organic molecules high amoutns of conjugation (or nitrogen hetero atoms) that can absorb solar radiation, resulting in an excited molecule with a high oxidative potential. We find that the 3C*-mediated aqueous oxidations of phenols are rapid and can dominate over *OH at low pH (
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